1. Field of the Invention
Example embodiments generally relate to nanoparticle taggants and, more particularly, relate to methods for constructing nanoparticle taggants for application to substrates.
2. Description of the Related Art
The issues of authentication and counterfeit deterrence can be important in many contexts. Bills of currency, stock and bond certificates, credit cards, passports, driver licenses, as well as many other legal documents all must be reliably authentic to be useful. Museums and art galleries face such challenges when authenticating works of art. Additionally, consumer products and other articles of manufacturing, such as pharmaceuticals, books, movies, software, etc., are frequently the subject of counterfeiting in the form of “pirated” versions or “knock-offs.”
A wide variety of attempts have been made to limit the likelihood of counterfeiting. Most such attempts tend to incorporate a unique identifier, or taggant, into the potentially counterfeited item. For example, some have utilized fluorescent compounds as identifiers for these items. Fluorescence occurs when a material is irradiated with electromagnetic radiation and at least some is absorbed. The emitted fluorescence can then be read by suitable means to ensure authenticity.